"The growth [in SRI] has been pretty remarkable," said Mark Peters, principal and member of the investment of Federal Street Advisors, a firm with a substantial focus on SRI and mission-related investing. According to the Forum for Sustainable and Responsible Investment, SRI investing grew 929 percent—a 13.1 percent compounded annual growth rate—between 1995 and 2014.
"More recently, you've had very sharp uptick," Peters said. From the beginning of 2012 to 2014, SRI assets in the U.S. grew 76 percent, to $6.57 trillion, up from $3.74 trillion. The number of stock and bond mutual funds that apply socially responsible mandates has also risen. In the U.S., there are now more than 100 sustainable mutual funds.
Read MoreHow to feel better about investing
Globally, interest in SRI is even more impressive. Between 2012 and 2014, global assets rose to $21.4 trillion, from $13.3 trillion—an increase of 61 percent, which outpaced the growth in total professionally managed assets, according to the 2014 Global Sustainable Investment Review.
Peters said much of the recent interest has to do with how the category has evolved. In the early days, it was more geared toward religious organizations that wanted to avoid one or two segments, such as companies involved with tobacco or alcohol. Over the last several years, however, the strategy has become more holistic, with a focus on identifying companies that are making positive social or environmental strides.